Protection switching is an essential feature in microwave and millimeter wave radio systems to meet system reliability objectives. There exist many different methods and systems to achieve an increase in system reliability and availability of protection switching. For example, a typical protection switching architecture may be realized as redundant sets of modules that are subparts of a higher level component and implement functions of the component. The component may be structured and controlled such that there are redundant modules for each feature or group of features of importance. In such an architecture there generally are at least two modules which implement each important function. These modules are typically referred to as redundant modules or redundant module sets. Prior art protection switching is generally constructed of one or more sets of these redundant modules, the premise being if a currently selected set fails, one other unselected set may be promptly substituted for the failed set and the component can resume providing communication or the relevant function.
A methodology and mechanism is required to control and communicate information regarding control of which of the redundant sets is the active or standby set. When this function is structured to operate without intervention of separate equipment or entities, it is commonly referred as automatic protection switching. In prior art radio systems, these switching decisions are generally made by a central controller. For example, prior art radio systems typically utilize a single central controller responsible for the control of protection switches based upon component and path alarms collected from various modules in a system. As a result, when the controller fails, no further switch decisions may be made, and the corresponding protection switch is frozen at its last state. Thus, any further component, equipment or path failures may result in a traffic or communication outage. Further, prior art mechanisms utilized to communicate with the central controller and any queuing associated therewith add delay in the reconfiguration of the component or equipment. Therefore, it is desirable to realize protection switching as a distributed solution so that communication may be protected from single failures.
Typical prior art automatic protection systems for network elements have also generally comprised, for example, redundant facility equipment wherein a detected failure in one of the redundant sides results in a switch from one redundant side to the other. In such an architecture, an entire line of protection equipment is substituted for another even if a failure occurred in only one place in the working channel. Such an approach is inflexible since it fails to maximize available equipment. Moreover, switching decisions are typically be made by the system controller and all information relevant to the protection switching decision must still be sent to the system controller. Since the system controller services all information in this type of architecture, a significant amount of time is required to accomplish the switchover, and all the elements on the data path are still required to be switched during a switching event.
It is apparent that the aforementioned processes are inefficient and fail to provide the necessary redundant protection switching required in microwave and millimeter wave radio systems. Accordingly, there is a need for a novel method and system that would overcome the deficiencies of the prior art. A further need exists for distributed protection switching in a microwave and millimeter wave radio systems. Thus, embodiments of the present subject matter may employ distributed protection switching architecture providing individual controllers on plural intelligent modules involved in a protection redundant path. Embodiments of the present subject matter may also provide distributed alarm collection and switch decision making as well as switch execution among the intelligent modules. Additional embodiments of the present subject matter may also provide an exchange of information between modules through an in-band communication protocol. Embodiments of the present subject matter thus eliminate single failure points that could render a protection switch inoperative, and thus improve a radio communication system's reliability.
An embodiment of the present subject matter provides a method for protecting a received data stream. The method comprises the steps of providing an active receiver and a standby receiver, each adaptable to receive a data stream and providing a plurality of data processing units (DPUs) operatively in communication with the active receiver and the standby receiver. The method further comprises measuring the quality of the data stream by the receivers, providing a signal to the plural DPUs as a function of a quality measurement of the received data stream, and processing the signal at ones of the plural DPUs. A switching may then be provided from at least one of the plural DPUs to switch the state of the active receiver to standby and the state of the standby receiver to active in response to the switching signal.
Another embodiment of the present subject matter provides a method for protecting a received data stream. The method comprises the steps of providing an active receiver and a standby receiver, each adaptable to receive a data stream on a traffic channel and providing a plurality of DPUs operatively in communication with the active and standby receivers. The method further comprises providing a switching signal from at least one of the plural DPUs to switch the state of the active receiver to standby and the state of the standby receiver to active as a function of a quality measurement of the received data stream via the traffic channel.
A further embodiment of the present subject matter provides a system for protecting a received data stream comprising a plurality of a predetermined number of active receivers, a plurality of a predetermined number of standby receivers, and a plurality of a predetermined number of DPUs. At least one of the plural active receivers and at least one of the plural standby receivers further comprise a switching controller adaptable to provide a signal as a function of a quality measurement of a received data stream, the controller adaptable to change the state of its respective receiver from standby to active or vice-versa. The DPUs further comprise a switching unit operatively in communication with the switching controllers, capable of receiving the signal, capable of providing a switching signal to at least one switching controller to change the state of the respective receiver.
An additional embodiment of the present subject matter provides a method for communicating between redundant controllers and plural microwave modules. The method comprises the steps of providing an active module and a standby module, each adaptable to transmit or receive a data stream and measure the quality of the data stream. The method further comprises providing a plurality of DPUs operatively in communication with the active module and the standby module, and communicating signals to ones of the plural DPUs from the active and standby modules as a function of a quality measurement of the received data stream via a channel carrying the data stream. The state of the active module may then be switched to standby and the state of the standby module to active in response to a switching signal provided from one of the plural DPUs via the channel.
These embodiments and many other objects and advantages thereof will be readily apparent to one skilled in the art to which the invention pertains from a perusal of the claims, the appended drawings, and the following detailed description of the embodiments.